Diffusion-weighted MR imaging of kidneys in renal artery stenosis

• Published in: European journal of radiology 2008-01, Vol.65 (1), p.148-153
• Main Authors: Yildirim, Erkan, Kirbas, Ismail, Teksam, Mehmet, Karadeli, Elif, Gullu, Hakan, Ozer, Ismail
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Diffusion Magnetic Resonance Imaging; Diffusion weighted MRI; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Female; Humans; Kidneys; Magnetic Resonance Angiography; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Radiology; Renal artery; Renal Artery Obstruction - diagnosis; Renal Circulation; Renovascular diseases; Stenosis; Urinary system involvement in other diseases. Miscellaneous
• ISSN: 0720-048X; 1872-7727
• DOI: 10.1016/j.ejrad.2007.03.007

Abstract Objective The purpose of our study was to evaluate perfusion and diffusion of kidneys in renal artery stenosis (RAS) and any correlation between stenosis and ADC values and whether this imaging modality may be a noninvasive complementary assessment technique to MR angiography before interventional procedures. Materials and methods Twenty consecutive patients suspected of having renal artery stenosis were evaluated with renal MR angiography to exclude stenosis and were then included in the study. Transverse DW multisection echo-planar MR imaging was performed. In the transverse ADC map, rectangular regions of interest were placed in the cortex on 3 parts (upper, middle, and lower poles) in each kidney. ADCs of the kidneys were calculated separately for the low, average, and high b -values to enable differentiation of the relative influence of the perfusion fraction and true diffusion. The ADC values of 39 kidneys (13 with renal artery stenosis and 26 normal renal arteries) were compared, and the relationship between stenosis degree and ADC values was calculated. Results RAS was detected in 11 of 20 (55%) patients with MRA. Thirteen of 39 kidneys demonstrated RAS, and 26 were normal. The ADClow (1.9 ± 0.2 versus 2.1 ± 0.2; P = .020), ADCaverage (1.7 ± 0.2 versus 1.9 ± 0.1; P = .006), and ADChigh (1.8 ± 0.2 versus 2.0 ± 0.1; P = .012) values were significantly lower in patients with kidneys with arterial stenosis than that in patients with kidneys with normal arteries. Statistical analysis revealed that stenosis degree correlated strongly with ADClow ( r = −.819; P = .001), ADCaverage ( r = −.754; P = .003), and ADChigh ( r = −.788; P = .001). The ADClow , ADCaverage , and ADChigh values were significantly lower in patients with kidneys with arterial stenosis than that in patients with kidneys with normal arteries. Conclusion We think that DW MR imaging of kidneys with RAS can help determine the functional status of a renal artery stenosis.